Diodes Incorporated ZHT431C01STZ

Overview

ZHT431C01STZ from Diodes Incorporated is a three-terminal adjustable precision shunt regulator with 1% initial tolerance, 2.5 V reference voltage, and programmable output voltage from 2.5 V to 20 V via external resistors. It delivers up to 100 mA cathode current, operates across –55°C to +125°C, and features 67 ppm/°C max temperature coefficient for stable voltage regulation in harsh environments.

For engineers reviewing the ZHT431C01STZ datasheet, ZHT431C01STZ pinout, ZHT431C01STZ application, or ZHT431C01STZ equivalent, key selection criteria include its TO-92 package compatibility, low dynamic impedance (0.75 Ω), wide operating temperature range, and use as a high-stability replacement for discrete Zener diodes in feedback and protection circuits.

Technical Context

The ZHT431C01STZ functions as a two-input, one-output shunt regulator: the reference input (VREF) senses voltage at the divider node, while the cathode (VZ) sinks current to maintain regulation. Its internal bandgap reference and error amplifier enable precise, temperature-compensated operation without external compensation components.

It operates in closed-loop shunt mode where external R1/R2 set output voltage per VOUT = VREF × (1 + R1/R2). Dynamic output impedance remains ≤0.75 Ω over 1–100 mA cathode current, and it maintains regulation down to 35 mA minimum cathode current (IZmin), supporting robust load transient response.

Key Specifications

Pinout & Package

Package: TO-92 (3-lead plastic through-hole), lead material: SnPb or Pb-free per marking suffix, body dimensions: 4.32–4.95 mm length × 3.30–3.94 mm width × 12.70–15.49 mm height.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar adjustable shunt regulator applications.

Compared with TL431ACDBVR and KA431AZTA, ZHT431C01STZ offers optimal balance of 1% accuracy, TO-92 through-hole compatibility, and extended temperature support - making it preferred for industrial power supplies and automotive body electronics where mechanical reliability and thermal margin are prioritized over ultra-fine voltage resolution.

Availability

ZHT431C01STZ is available at Aetrix Electronics and suitable for switch-mode power supply feedback, voltage monitoring, overvoltage protection, and shunt regulator replacement applications requiring stable component supply across extended temperature ranges.

Supply support for ZHT431C01STZ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design, manufacturing, and distribution operations across Asia and the Americas.

The ZHT431 belongs to Diodes' precision shunt regulator product line, engineered specifically for high-reliability voltage reference and regulation in industrial, automotive, and telecom power systems where extended temperature operation and long-term stability are essential.

FAQ

What is the minimum cathode current required for regulation in ZHT431C01STZ?

The ZHT431C01STZ requires a minimum cathode current (IZmin) of 35 mA to maintain regulation at VREF = 2.50 V, as specified in the Electrical Characteristics table under recommended operating conditions. This value is confirmed across the full –55°C to +125°C temperature range and must be met in all active regulation states to ensure output voltage accuracy and stability.

Can ZHT431C01STZ be used in place of a standard Zener diode?

Yes - ZHT431C01STZ is explicitly designed as a performance-enhanced replacement for discrete Zener diodes. Its programmable output, tighter tolerance (1%), lower temperature coefficient (≤67 ppm/°C), and higher current capability (up to 100 mA) provide superior regulation accuracy and thermal stability compared to typical 5% tolerance Zeners, especially in feedback and protection circuits.

What is the dynamic output impedance of ZHT431C01STZ and why does it matter?

ZHT431C01STZ has a dynamic output impedance (RZ) of 0.75 Ω, measured at VZ = VREF with cathode current varying from 1 mA to 100 mA. This low impedance ensures minimal output voltage deviation (<75 mV) under 100 mA load transients - critical for maintaining loop stability in SMPS feedback paths and accurate threshold detection in voltage monitors.

Does ZHT431C01STZ require external compensation capacitors?

No - ZHT431C01STZ is internally compensated and operates stably with standard RC feedback networks. The datasheet confirms stable pulse response and open-loop gain behavior up to 1 MHz without added capacitance. External capacitors (e.g., 0.01 µF) may be used for noise filtering but are not required for basic regulation or loop stability in typical applications.